Chondroma of the external auditory canal

Chondroma, a benign tumour which is common at many sites in the body, has not been reported in the English literature in the bony external auditory canal. The first such case at this anatomical site is described and the pathogenesis is considered.     

Paraganglioma of the external auditory canal

A rare case of paraganglioma of the external auditory canal is presented. It was treated by excision and no recurrence has been noted after 18 months of follow up.     

Programmed cell death contributes to postnatal lung development

The rat lung undergoes the phase of maturation of the alveolar septa and of the parenchymal microvascular network mainly during the third postnatal week. Speculating that programmed cell death may contribute to the thinning of the alveolar septa, we searched for the presence of DNA fragmentation in rat lungs between postnatal days 6 and 36 using the TUNEL procedure. The number of positive nuclei was compared at different days. We observed an 8-fold increase of programmed cell death toward the end of the third week as compared to the days before and after this time point. The precise timing of the appearance of the peak depended on the size of the litter. Double-labeling for DNA fragmentation (TUNEL) and for type I and type II epithelial cells (antibodies E11 and MNF-116), as well as morphologic studies at electron microscopic level, revealed that during the peak of programmed cell death mainly fibroblasts and type II epithelial cells were dying. While both dying cell types were TUNEL-positive, nuclear fragments and apoptotic bodies were exclusively observed in the dying fibroblasts. We conclude that programmed cell death is involved in the structural maturation of the lung by reducing the number of fibroblasts and type II epithelial cells in the third postnatal week. We observed that the dying fibroblasts are cleared by neighboring fibroblasts in a later stage of apoptosis, and we hypothesize that type II epithelial cells are cleared by alveolar macrophages in early stages of the programmed cell death process.     

Merkel cell carcinoma of the external auditory canal invading the intracranial compartment

Heparin-induced thrombocytopenia (HIT) is a common drug induced autoimmune condition. The thrombocytopenia is caused in most cases by an antibody directed against the complex PF4/heparin. Recently, we have induced an experimental model of HIT by idiotypic manipulation. To confirm further the idiotypic involvement of HIT, we have treated successfully three patients with HIT with high-dose intravenous gamma-globulin (IVIG). Our three patients joint other two cases previously reported who were treated with IVIG and point to the efficacy of this type of therapy with minimal side effects. IVIG suppression of the anti-PF4/heparin autoantibody may support the idiotypic etiology of HIT.     

Programmed cell death and radioresistance

Whereas apoptosis is a critical mode of cell deletion in normal organism development, apoptotic cells are also observed in tumors, especially following cytotoxic treatments, leading to questions about their role in tumor response to therapy. We have conducted a series of studies using murine tumor models and found that the ability of the tumor cells to undergo apoptosis correlates with tumor response to radiation. The best correlation was with the pretreatment apoptotic index, suggesting that apoptosis in some tumors may govern radiocurability by regulating the number of tumor clonogens. However, other roles for apoptosis in tumor response to radiation have not been ruled out. One of the important observations that has come from this work has been the heterogeneity in apoptosis propensity both within the cell population of a given tumor and among different types of tumors. Such findings underscore the fact that apoptosis is under complex genetic control and that some of the same oncogenes and tumor suppressor genes that are responsible for tumor initiation and progression to malignancy also dictate the apoptotic response to treatment. Understanding the biochemical and molecular pathways that govern this process may ultimately allow the development of strategies for modulating apoptosis for therapeutic benefit.     

Fiberscope-assisted evaluation of prereconstructed and postreconstructed external auditory canal

The malignant tumors of the external auditory canal often invade the middle ear area through the narrow canal, so it is difficult to determine the surgical excisional margin. A patient undergoing external auditory canal reconstruction following excision of a squamous cell carcinoma using a chondrocutaneous flap and fiberscope-assisted preoperative and postoperative diagnoses are described. We obtained good patency of the canal postoperatively. This technique is quite simple and easy to use. We believe fiberscope-assisted surgery is useful for extracting lesions in small areas. In the future, its application will extend to the area of plastic surgery.     

Programmed cell death during Drosophila embryogenesis

The deliberate and orderly removal of cells by programmed cell death is a common phenomenon during the development of metazoan animals. We have examined the distribution and ultrastructural appearance of cell deaths that occur during embryogenesis in Drosophila melanogaster. A large number of cells die during embryonic development in Drosophila. These cells display ultrastructural features that resemble apoptosis observed in vertebrate systems, including nuclear condensation, fragmentation and engulfment by macrophages. Programmed cell deaths can be rapidly and reliably visualized in living wild-type and mutant Drosophila embryos using the vital dyes acridine orange or nile blue. Acridine orange appears to selectively stain apoptotic forms of death in these preparations, since cells undergoing necrotic deaths were not significantly labelled. Likewise, toluidine blue staining of fixed tissues resulted in highly specific labelling of apoptotic cells, indicating that apoptosis leads to specific biochemical changes responsible for the selective affinity to these dyes. Cell death begins at stage 11 (approximately 7 hours) of embryogenesis and thereafter becomes widespread, affecting many different tissues and regions of the embryo. Although the distribution of dying cells changes drastically over time, the overall pattern of cell death is highly reproducible for any given developmental stage. Detailed analysis of cell death in the central nervous system of stage 16 embryos (13-16 hours) revealed asymmetries in the exact number and position of dying cells on either side of the midline, suggesting that the decision to die may not be strictly predetermined at this stage. This work provides the basis for further molecular genetic studies on the control and execution of programmed cell death in Drosophila.     

Impression-material foreign bodies of the middle ear and external auditory canal

Twenty-nine evaluable patients with endometrial cancer were treated with amonafide 300 mg/m2 for 5 consecutive days every 3 weeks. Two partial responses (8%) were seen. Hematologic toxicity was severe or life-threatening in 13 patients occurring as follows: leukopenia in 13 patients (45%); thrombocytopenia in 10 patients (34%); granulocytopenia in 13 patients (45%); and anemia in four patients (14%). In view of the low response rate and high toxicity, this dose schedule of amonafide does not warrant further investigation in endometrial cancer.     

The human external auditory canal, secretory system--an ultrastructural study

Human external auditory canal skin, with a special emphasis on the secretory system, was studied by light, transmission electron and scanning electron microscopy. Two types of secretory glands were observed: modified apocrine (ceruminous) and sebaceous. The sebaceous secretory cellere homogeneous; on the other hand, modified apocrine secretory cells contained heterogeneous secretory granules. They were ither dark granules or light granules. Evidence to support both the apocrine as well as the eccrine mode of secretion was noted in the modified apocrine gland. This finding is partly in agreement with early reports based on light microscopy with suggested only an apocrine mode and data based on transmission electron microscopy which showed only the eccrine mode. Significance of the secretion by the external ear canal and its role in a local immune defense system is discussed.     

Perineurioma: an unusual cause of an external auditory canal polyp

BACKGROUND: Home parenteral nutrition (HPN) is used to treat intestinal failure. A minority of HPN patients are dependent on opiates and benzodiazepines to control pain and anxiety. The aim of this study was to determine what effects such drug dependence had on patient outcomes. METHODS: Ten dependent patients were prospectively compared with 10 well-matched, nondependent HPN patients for the same 12-month period. Episodes of line sepsis and other complications were documented and the cost of treatment estimated. Health status was measured using the SF36 and EuroQol instruments. RESULTS: The dependent group had significantly more episodes of central line sepsis (p = .0007) as well as other complications (p = .0002). This led to significantly longer periods of inpatient care (p = .0004) and therefore higher costs of treatment. Health status was lower in the dependent group; they reported more pain (p = .04) and less energy (p = .04). CONCLUSIONS: The complication rate and increased cost of treatment for opiate- and sedative-dependent patients receiving HPN significantly detract from the overall outcome of this therapy.     

Twenty-one cases of malignant tumor of the external auditory canal or middle ear

We have assessed the effects of intraplantar local anaesthetics (bupivacaine and lignocaine) on carrageenan-induced oedema, mechanical allodynia and spinal c-fos protein expression. Mechanical allodynia was evaluated using the vocalization threshold to paw pressure (VTPP) every 30 min until 60, 180 or 240 min after administration of carrageenan. Peripheral oedema, mechanical allodynia and spinal c-fos protein expression were maximal 180 min after carrageenan. Lignocaine did not influence either oedema or VTPP, but reduced spinal c-fos expression at 60 min after carrageenan without later effects. Bupivacaine induced an increase in VTPP at 30 and 60 min, limitation of oedema at 60 min and a reduction in spinal c-fos expression at 60 and 180 min, but these effects were not present 240 min after carrageenan. Intraplantar infiltration with lignocaine and bupivacaine before carrageenan transiently limited signs of inflammatory pain but did not prevent them.     

Programmed cell death in the root cortex of soybean root necrosis mutants

The soybean root necrosis (rn) mutation causes a progressive browning of the root soon after germination that is associated with accumulation of phytoalexins and pathogenesis-related proteins and an increased tolerance to root-borne infection by the fungal pathogen, Phytophthora sojae. Grafting and decapitation experiments indicate that the rn phenotype is root-autonomous at the macroscopic level. However, the onset and severity of browning was modulated in intact plants by exposure to light, as was the extent of lateral root formation, suggesting that both lateral roots and the rn phenotype could be directly or indirectly controlled by similar shoot-derived factors. Browning first occurs in differentiated inner cortical cells adjacent to the stele and is preceded by a wave of autofluorescence that emanates from cortical cells opposite the xylem poles and spreads across the cortex. Before any visible changes in autofluorescence or browning, fragmented DNA was detected by TUNEL (Terminal deoxynucleotidyl transferase-mediated dUTP-digoxigenin nick end labeling) in small clusters of inner cortical cells that subsequently could be distinguished cytologically from neighboring cells throughout rn root development. Inner cortical cells overlying lateral root primordia in either Rn or rn plants also were stained by TUNEL. Features commonly observed in animal cell apoptosis were confirmed by electron microscopy but, surprisingly, cells with a necrotic morphology were detected alongside apoptotic cells in the cortex of rn roots when TUNEL-positive cells were first observed. The two morphologies may represent different stages of a common pathway for programmed cell death (pcd) in plant roots, or two separate pathways of pcd could be involved. The phenotype of rn plants suggests that the Rn gene could either negatively regulate cortical cell death or be required for cortical cell survival. The possibility of a mechanistic link between cortical cell death in rn plants and during lateral root emergence is discussed.     

Restoration of external auditory canal by filling mastoid cavity with carbon pellet

Percutaneous suspension plasty, using Eickenberg's double-needle applicator, is a further development of the semi-open endoscopic method suggested by Stamey for precluding urinary incontinence in women. The operative technique is outlined, and the follow-up results in 53 patients are analyzes. This is a contribution to the broadening scope of endourologic and percutaneous operative technique.     

Programmed cell death in bovine mammary tissue during lactation and involution

Cessation of milk removal causes mammary tissue involution, which in rodents is characterized by extensive tissue degeneration and loss of the majority of luminal epithelial cells by apoptosis. In contrast, bovine mammary tissue shows little histological evidence of tissue remodelling between lactations. In this study, we combined histology with molecular biology to examine the cellular and molecular changes in bovine mammary tissue on cessation of milking. Oligonucleosomal laddering of genomic DNA extracted from lactating tissue indicated that a proportion of cells were dying by apoptosis. This was confirmed by terminal deoxynucleotide transferase-mediated deoxyuridine nick end-labelling of apoptotic cells in lactating tissue sections (TUNEL). One week after cessation of milking, alpha-lactalbumin and alpha S1-casein messenger RNA (mRNA) abundance had decreased by 99 and 85%, respectively, whereas lactoferrin mRNA had increased 20-fold. Drying off was also accompanied by an increase in oligonucleosomal laddering of genomic DNA, and by an increase in the proportion of TUNEL-positive cells, which were localized preferentially in regions where alveolar structure had deteriorated. Therefore, termination of lactation was associated with partial loss of the mammary cell population and dedifferentiation of the remainder.     

Reconstruction of the external auditory canal with a laterocervical twisted flap (snail flap)

A case of circumferential reconstruction of the external auditory canal following basal cell carcinoma is described using a laterocervical tubed flap. One-stage reconstruction with a single flap, absence of donor-site deformity, and easy dissection are the main advantages of the procedure, which also can be conveniently used to reconstruct part of the concha and the tragal region.     

Radiation therapy in the management of carcinoma of the external auditory canal, middle ear, or mastoid

Twenty-three patients with squamous-cell carcinoma of the external auditory canal, middle ear, or mastoid were treated with combined surgery and irradiation, giving a 5-year NED rate of 48% (11/23). Except in extremely early lesions without bone involvement, treatment by radiation therapy alone was rarely successful and is not recommended. The most serious complication was osteoradionecrosis of the temporal bone; this occurred in 5 patients, all of whom received more than 2,100 rets due to faulty radiotherapeutic technique.     

Adenoid cystic carcinoma of the external auditory canal: correlation between histological features and MRI appearances

A rare case of adenoid cystic carcinoma of the external auditory canal with magnetic resonance imaging appearances is reported. Both T1 weighted and T2 weighted MR images showed the tumour as a hypointense mass, although there was marked contrast enhancement. Microscopic examination of the resected tumour showed a preponderance of solid tumour cell nests. According to previous reports, these pathological and radiological findings indicate a poor prognosis.     

Programmed cell death during the earliest stages of spinal cord development in the chick embryo: a possible means of early phenotypic selection

The spatiotemporal distribution of cell death in the chick embryo neural tube and spinal cord (brachial region) was examined between stage (St.) 12 and 22, in plastic semithin sections. Between St. 12 and 16, the total number of pycnotic cells per segment was low, whereas after St. 16 the number of pycnotic cells was substantially increased. Between St. 17 and 19 three cell death foci or regions could be recognized. One region, the dorsal pycnotic zone, was located in the most dorsal part of the spinal cord, including the neural crest, with the highest number of pycnotic cells observed at St. 18. The second region, or ventral pycnotic zone, was located between motoneurons and the floor plate and had the highest number of dying cells at St. 17. The third region, the floor plate pycnotic zone, was located in the midportion of the floor plate and had the greatest amount of cell death at St. 19. Although low numbers of pycnotic cells were also observed in other regions between St. 17 and 19, no pycnotic cells were found in the ventrolateral region that gives rise to motoneurons. Ultrastructural observations as well as data from in situ nick end labeling indicate that the pycnotic cells observed in the neural tube die by apoptosis and that the debris from the dead cells is phagocytized primarily by adjacent healthy neuroepithelial cells. Although the spatiotemporal distribution of pycnotic cells suggests that cell death at these early stages could play a role in establishing the pioneer axonal pathway for spinal commissural neurons, preliminary observations following perturbations of cell death do not support this notion. Alternatively, early cell death may be involved in the regulation of cellular patterning along the dorsoventral axis of the neural tube by a kind of negative selection of specific progenitor cells.     

Programmed cell death in the tobacco hornworm, Manduca sexta: alteration in protein synthesis

The metamorphic death of the labial glands of the tobacco hornworm, Manduca sexta, occurs during a 4 day period during larva-to-pupa metamorphosis. The earliest changes marking the death of the cell, all occurring on the first day, are a sharp drop in protein synthesis, coupled with the selective survival or upregulation of a few messages. An early rearrangement of the rough endoplasmic reticulum is presumably related to the generalized decrease in protein synthesis. Lysosomal acid phosphatase also begins to increase very early, and ultimately the bulk of the cytoplasm is destroyed in autophagic vacuoles, but activation of lysosomes does not account for the decreased rate of synthesis. The mechanism by which most protein synthesis is depressed remains under investigation.